Create internetmonitoring service

Adding Internet Monitoring Stack for tracking speed and ping over time with Prometheus + Grafana

Note purposefully haven't added the setting to define a fixed SPEEDTEST_SERVER on the speedtest-exporter container as per the docs:

We strongly discourage you from setting a specific server. If the server that you are using to make the tests stops working, your exporter won't be able to do the tests and you won't get the metrics. However I've defined this on my own setup.

Also good to note that there's an existing current issue showing "Annotation Query Failed", but doesn't affect functionality. I'm adding as-is and will keep up to date :)

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